1. Field of the Invention
This invention relates generally to electronic imaging devices and more particularly to a system and method for generating timing signals in an electronic imaging device.
2. Description of the Background Art
The efficient operation and use of electronic imaging devices provide computer users with new and effective ways to capture and process various types of image data. Electronic imaging devices typically include special electronic image sensors which convert a selected image into electronic data. These electronic image sensors conventionally include a series of discrete picture elements (or pixels) which convert light reflected from a photographic target into electrical energy that is then shifted out of the image sensor device. Due to the complexity of the high-speed process involved in shifting captured image data out of the image sensor, electronic imaging devices require a series of precise timing pulses to successfully gate the image data from the image sensor. Electronic imaging devices (such as digital cameras) typically include a timing generator device which effectively generates and provides the precise timing pulses to the electronic image sensor.
Referring now to FIG. 1, a block diagram of a conventional fixed timing generator device 60 is shown. The FIG. 1 timing generator 60 includes fixed timing module 1 (62) through fixed timing module "N" (68) which each generate a discrete and unchangeable output signal. For example, timing module 1 (62) includes a state machine 74 which receives a high-speed clock signal on line 70 and responsively provides an output to a first input of AND gate 76. A gate signal on line 72 is applied to a second input of AND gate 76 to produce a fixed output signal on line 78. The FIG. 1 timing generator 60 thus produces a series of fixed timing signals which are specifically designed to operate with a particular corresponding image sensor device. Because of their dedicated functionality, conventional fixed timing generators 60 therefore exhibit a significant lack of flexibility.
Other conventional timing generators use various other techniques to generate programmable timing signals. For example, one prior art timing generator is limited to OR-tying several pulse generation modules together. This approach limits the number of transitions on any one output and thus prevents dynamically changing the number of transitions during pulse signal generation. Another prior art timing generator system requires a central processing unit to generate a specific interrupt signal so that the system software can responsively manipulate a specific timing pulse. This approach is excessively software intensive, since the software must repeatedly access and process the timing signals on a continuing basis.
Electronic image sensor devices are currently evolving to become increasingly more complex and are thus requiring timing generators with more advanced capabilities and greater flexibility. Therefore, an improved system and method are needed for generating timing signals in an electronic imaging device.